Field of the Invention
The present invention relates to a golf club head.
Description of the Related Art
There are proposed techniques to provide a concave portion in a golf club head to improve the performance of the golf club head (U.S. Pat. Nos. 4,065,133 and 3,997,170, Japanese Patent Laid-Open Nos. 10-277181 and 8-173578, and Japanese Utility Model Registration No. 03023452). Such a concave portion may influence the air resistance to the golf club head at impact.
A golf club head includes a hosel portion in which a shaft is inserted. This hosel portion can adversely affect the airflow which flows around the golf club head at impact, thereby worsening the air resistance. If the air resistance worsens, the head speed decreases, and the distance performance of the golf club head deteriorates.